DE3005069A1 - 2-Oxo-6-hydroxy-1,2-di:hydro-pyridine-5- carboxylic acid derivs. - prepd. by reaction of alkoxy:methylene-malonate cpds. with substd. acetamide cpds. - Google Patents

Abstract

2-Oxo-6-hydroxy-1,2-dihydro-pyridine -5-carboxylic acid derivs. of formula (I) and their alkali and alkaline earth salts are new. X is CN, NO2, acyl, the carboxylic acid ester residue, substd. carbamoyl or sulphamoyl, alkylsulphonyl, arylsulphonyl, or a sulphonic acid ester residue; R1 is H, opt. substd. alkyl, cycloalkyl, alkenyl, aralkyl or aryl; and R2 is H, opt. substd. alkyl, cycloalkyl, alkenyl, aralkyl or phenyl. (I) are useful as intermediate for pyridone derivs. of formula(IV), which in turn are of interest because of their pharmacological activity. (I) are also useful as intermediate for other cpds. useful as pharmaceuticals and plant protection agents.

Description

Pyridone derivatives, their preparation and their use

The present invention relates to new pyridone derivatives of the formula I. wherein X is cyano, vitro, acyl, the carboxylic acid ester group, substituted carbamoyl or sulfamoyl, alkyl or aryl sulfone, the sulfonic acid ester group, R1 is hydrogen, optionally substituted alkyl, cycloalkyl, alkenyl, aralkyl or aryl and R2 is hydrogen, an optionally substituted alkyl, cycloalkyl, alkenyl , Aralkyl or phenyl, their alkali and alkaline earth salts, their preparation by condensation of malonic ester derivatives of the formula II with acetamide derivatives of the formula III and their use for the technically simple, ecologically and toxicologically safe and economical production of known, technically valuable compounds of the formula ZV The compounds of the formula I can exist in several tautomeric forms. For the sake of simplicity, they are only written here in one of the possible tautomeric forms. It goes without saying that this description includes each of the possible tautomeric forms.

The salt formation takes place on the OH group of the pyridone earth, i.e. by exchanging the proton involved in the tautomerism by an alkali or Alkaline earth cation. If R is hydrogen, it becomes hydrogen in the case of salt formation also replaced by an alkali or alkaline earth cation.

As alkali or alkaline earth metal salts are in particular the sodium and potassium salt of interest.

Acyl groups for which X stands are alkylcarbonyl with 1 to 8 carbon atoms, in the phenyl nucleus optionally by one or two substituents from the group halogen, in particular fluorine, chlorine, or bromine, nitro, cyano, alkoxy with 1 to 4 0 atoms, Benzylcarbonyl, phenethylcarbonyl or substituted alkyl with 1 to 4 carbon atoms Benzoyl, or benzoyl substituted by alkoxycarbonyl having 2 to 5 carbon atoms.

Carboxylic ester groups for which X is> are alkoxycarbonyl with 1 to 8 0 atoms, C1 to C4 alkoxy or C1 to C4 alkanoylalkoxycarbonyl with 4 up to 9 carbon atoms, cycloalkoxycarbonyl with 6 to 9 0 atoms, optionally in the phenyl nucleus by one or two substituents from the group halogen, in particular fluorine, chlorine and substituted bromine, alkoxy with 1 to 4 carbon atoms, alkyl with 1 to 4 carbon atoms Benzyloxycarbonyl, phenethyloxycarbonyl, or phenoxycarbonyl.

Optionally substituted carbamoyl or sulfamoyl groups for the X corresponds to the formulas -CONR4R5 and

-So2NR4R5, in which R4 and R5 are identical or different and are hydrogen, Alkyl with 1 to 8 0 atoms, C1-C4 alkoxy and C1-C4 alkanoyloxy alkyls with 2 to 8 0 atoms, cycloalkyl with 5 to 8 carbon atoms and optionally in the phenyl nucleus one or two substituents from the group halogen, alkoxy with 1 to 40 atoms, alkyl are benzyl, phenetyl or phenyl substituted by 1 to 4 carbon atoms.

Alkyl or aryl sulfone, for which X is, are the groups alkylsulfonyl with 1 to 8 0 atoms, cycloalkylsulfonyl with 5 or 6 carbon atoms in the phenyl nucleus, if appropriate by one or two substituents from the group halogen, alkoxy with 1 to 4 0 atoms, Alkyl with 1 to 4 carbon atoms substituted benzylsulfonyl, phenethylsulfonyl and Phenylsulfonyl.

Sulfonic acid ester groups for which X stands are alkoxysulfonyloxy with 1 to 8 0 atoms, cycloalkoxysulfonyloxy with 5 or 6 carbon atoms in the phenyl nucleus optionally by one or two substituents from the halogen or alkoxy group 1 to 4 0 atoms, alkyl benzyloxysulionyloxy substituted with 1 to 4 carbon atoms, Phenethoxysulfonyloxy, phenoxysulfonyloxy.

X preferably represents cyano, nitro, alkylcarbonyl with 1 to 8, in particular 1 to 4 carbon atoms, in the phenyl nucleus optionally by a substituent of the group Chlorine, nitro, alkoxy with 1 to 4 0 atoms, in particular methoxy, alkyl with 1 to 4 0 atoms, especially methyl, substituted benzoyl, alkoxycarbonyl with 1 to 8 0 atoms, C1 to C4 alkoxy or C1 to C4 alkanoylalkoxycarbonyl with 4 to 9 C atoms, in the phenyl nucleus, optionally by a substituent from the group chlorine, Alkoxy with 1 to 4 0 atoms, in particular methoxy, alkyl with 1 to 4 0 atoms, in particular Methyl substituted phenoxycarbonyl, carbamoyl or sulfamoyl of the formulas -CONR4R5 or -SO2NR4R5, in which R4 and R5 are identical or different and are alkyl with 1 to 4 carbon atoms, C1-C4 alkoxy and C1-C4 alkanoyloxyalkyl with 3 to 7 carbon atoms a substituent from the group consisting of chlorine, methoxy or methyl substituted phenyl and one of the substituents R4 or R5 can also be hydrogen, alkylsulfonyl with 1 to 4 0 atoms, in the phenyl nucleus optionally by a substituent of Group chlorine, alkoxy with 1 to 4 carbon atoms, in particular methoxy, alkyl with 1 to 4 0 atoms, in particular methyl, substituted phenylsulfonyl, alkoxysulfonyl with 1 to 8 0 atoms, in the phenyl nucleus optionally by a substituent of the group Chlorine, alkoxy with 1 to 4 0 atoms, in particular methoxy, alkyl with 1 to 4 0 atoms, in particular Methyl substituted phenoxysulfonyl.

Individual examples of substituents for which X can stand are cyan, Nitro, acetyl, propionyl, butyryl, o-, m- or p-methylbenzoyl, o-, m- or p-methoxybenzoyl, o-, m- or p-chlorobenzoyl, o-, m- or p-nitrobenzoyl, o-, m- or p-cyanobenzoyl, Methoxycarbonyl, ethoxycarbonyl, n- and iso-propoxycarbonyl, n- and iso-butoxycarbonyl, Phenoxycarbonyl, methylcarbamoyl, ethylcarbamoyl; n- or iso-propylcarbamoyl, N, N-dimethylcarbamoyl, methoxyethylcarbamoyl, isopropoxyethylcarbamoyl, methoxysulfonyl, Ethoxysulfonyl, phenoxysulfonyl, o-, m- or p-tolyloxysulfonyl, methylsulfonyl, Phenylsulfonyl, N-methylsulfamoyl or N, N-dimethylsuliamoyl.

Particularly preferred individual radicals for which X stands are cyano, methylcarbamoyl, Acetyl, benzoyl, ethoxycarbonyl, phenoxycarbonyl, sulfamoyl, methoxysulfonyl, phenoxysulfonyl and l-pyridinium.

Optionally substituted alkyl, which can stand for R1, is straight-chain or branched and has 1 to 12 carbon atoms, the carbon chain being replaced by 1 to 5 Oxygen atoms or -NR³ groups interrupted and that by hydroxy, alkanoyloxy with 1 to 4 carbon atoms, cycloalkoxy with 5 to 8 carbon atoms, aryl with 6 to 12 carbon atoms, Aryloxy with 6 to 12 carbon atoms, cyano, amino, phenylamino, alkanoylamino with 1 to 6 carbon atoms, benzoylamino, cyclic amides bonded to nitrogen with 5 to 7 ring members, Alkoxycarbonyl with 2 to 9 carbon atoms, hydroxyalkoxycarbonyl with 3 to 5 carbon atoms may be substituted and R3 can be hydrogen, straight-chain or branched alkyl with 1 to 6 carbon atoms or alkanoyl with 1 or 2 carbon atoms.

Cycloalkyl radicals for R1 have 3 to 8 and alkenyl radicals 3 to 6 C atoms aralkyl or aryl radicals, for which R1 can stand, are aralkyl with 7 to 12 carbon atoms, the alkyl chain of which is still substituted by OH be can, or aryl with 6 to 12 0 atoms, with phenyl nuclei contained in R1 still through Alkyl with a total of up to 6 0 atoms, chlorine or alkoxy with up to 4 carbon atoms and Naphthyl nuclei can be substituted by methyl or ethyl.

R1 is preferably hydrogen, straight-chain or branched Alkyl with 1 to 12 0 atoms, whose carbon chain is through a -NR3 group or interrupted by 1 to 5, preferably 1 - 2 oxygen atoms and that by hydroxy, Alkanoyloxy with 1 to 4 0 atoms, cycloalkoxy with 5 or 6 0 atoms, phenyl, phenoxy, Cyano, amino, phenylamino, alkanoylamino with 1 to 6, in particular 2 to 4 0 atoms, Benzoylamino, alkoxycarbonyl with 2 to 50 atoms, Iiydroxyethoxycarbonyl substituted can be, cycloalkyl with 5 or 6 carbon atoms, alkenyl with 3 or 4 0 atoms, benzyl, Phenethyl, phenylpropyl, phenylbutyl, p-hydroxy-p-phenethyl or phenyl, where in Phenyl nuclei contained in R1 may also be substituted by methyl, chlorine or methoxy can and non-cyclic, saturated substituents are still particularly advantageous.

Individual examples of substituents for which R stands: hydrogen, Methyl, ethyl, normal- or iso-propyl, -butyl, -pentyl or -hexyl, p-ethylhexyl, p-hydroxyethyl, y-hydroxypropyl, -p-hydroxypropyl, 4) -hydroxyhexyl, p-methoxyethyl, y-methoxy or y-ethoxypropyl, y-iso-propoxypropyl, y-iso-butoxypropyl, J-cyanopentyl, 2- (2-Hydroxyethoxy) -ethyl, 3- (2-Hydroxysthoxy) -propyl- (1), 3- (3-Hydroxypropoxy) -propyl- (1), 3- (4-Hgdroxy-butoxy) -propyl- (1), 3- (6-hydroxyhexoxy) -propyl- (1), 5-hydroxy-heptyl- (2), 5-hydroxy-5-methyl-heptyl- (2) 3-benzyloxy-propyl- (1), 3-phenoxy-propyl- (1) 3-cyclohexoxypropyl- (1), 3- (2-phenoxyethoxy) -propyl- (1), 9-aminoethyl, 4-aminobutyl- (1), 6-aminohexyl- (1), 3-N, N-dimethylamino-propyl- <1), 2-N, N-diethylamino-ethyl, d-N-methylamino-butyl- ( 4-N-butylaminobutyl- (1), 2-N, N-dibutylamino-ethyl, benzyl, phenethyl, phenylpropyl, Phenylbutyl, p-hydroxy-p-phenethyl, cyclohexyl, cyclooctyl, phenyl or by methyl, Chlorine or methoxy substituted phenyl.

Individual preferred radicals are e.g. B. butyl, hexyl, iso-octyl, 2-ethyl-hexyl, β-Hydroxyethyl, γ-hydroxypropyl, p-Amino-ethyl, γ-Dimethylaminopropyl, Phenethyl-p-Butylphenyl, 2,4-diisopropylphenyl, 2,4-diethoxybenzyl, 2,4-dimethoxyphenethyl and especially Hydrogen, methyl, ethyl, f3-methoxyethyl, γ-methoxypropyl.

Optionally substituted alkyl radicals represented by R2 are straight-chain or branched alkyl having 1 to 8 carbon atoms, which is also replaced by alkoxy having 1 to 4 0 atoms, Aralkoxy with 7 to 12 carbon atoms or aryloxy with 6 to 12 carbon atoms be substituted can.

² Cycloalkyl radicals standing for R have 5 to 8, alkenyl radicals 3 to 6 C atoms Aralkyl radicals, for which R² stands, have 7 to 12 C atoms.

R2 is preferably hydrogen, straight-chain alkyl with 1 to 8, in particular 1 to 4 carbon atoms, followed by alkoxy with 1 to 4 0 atoms, in particular Methoxy and ethoxy as well as benzyloxy, phenethoxy, phenylpropoxy or phenylbutoxy or phenoxy can be substituted, cyclopentyl or cyclohexyl, benzyl, phenethyl, Phenylpropyl, phenylbutyl or phenyl. Alkyl radicals are particularly preferred for R2 with 1 to 4 carbon atoms.

Individual examples for radicals R2 are methyl, ethyl, propyl, isopropyl, Butyl- (1), butyl .- (2), 2-methyl-propyl- (1), 2-methyl-propyl- (2), pentyl, isopentyl, Hexyl, heptyl, octyl, 2-ethyl-hexyl- (1), 4-methoxy-butyl- (l), 2-butoxy-butyl- (l), 2-butoxy-ethyl, 2-thoxy-ethyl, 6-ethoxy-hexyl- (1), 6-benzyloxy-hexyl- (1), 2-phenylbutoxy-ethyl, 4-phenoxy-butyl- (1) 6-phenoxy-2-ethyl-hexyl- (1), 2-phenoxy-ethyl, 2- (4-butyl-phenoxy) -propyl- (l), 2- (2,4-diisopropyl-phenoxy) -ethyl, allyl, methallyl, cyclopentyl, cyclohexyl, benzyl, Phenethyl, phenylbutyl, phenyl, 4-butylphenyl.

Preferred individual examples for R2 are methyl, ethyl, propyl, butyl, 2-methoxy-ethyl, 2-ethoxy-ethyl, 4-methoxybutyl, benzyl.

In the event that R2 stands for hydrogen, the substituent is -COOR2 of the compounds of the formula I according to the invention have a carboxyl group. In alkaline Medium this is capable of salt formation by exchanging the hydrogen standing for R2 against a metal cation. This case naturally occurs when the alkali or alkaline earth salts of the compounds of the formula I are to be prepared. It then not only the tautomeric proton of the OH groups in the 6-position of the Pyridon (2) nucleus, but also the proton standing for R2 against an alkali or Alkaline earth exchanged.

The compounds of the formula I according to the invention are prepared by adding a malonic ester derivative of the formula II ² wherein R has the meanings given in claims 1 and 4 with the exception of hydrogen and R is alkyl with 1 to 4 carbon atoms, in an organic solvent in the presence of a base at temperatures of -20 to 1500C with an acetamide derivative of the formula III X-CH -CONH-R¹ (III) 2 in which X and R1 have the meanings given in claims 1 and 3, condensed and, if desired, then the free compound of the formula I from the resulting salt of the compound of the formula I by the action of a dilute strong acid I produces and / or saponifies the ester group -COOR to the carboxyl group by acidic or alkaline treatment.

The malonic ester derivatives of the formula II are, for. T. technically produced Commercial products, but they can also be easily obtained by Knoevenagel condensation can be easily prepared from formic acid derivatives and malonic esters.

The conditions for this can be found in the literature, for example "Organic Reactions "Vol. 15, pp. 204-599 (1967). Also the acetamide derivatives of the formula III are either common commercial products or can be made according to known Process are produced.

Solvents used to carry out the reaction of the malonic ester derivatives with the acetamide derivatives are lower alanols, lower diols, diol mono- or diet ethers, cyclic ethers, aromatic hydrocarbons, especially simple ones Benzene derivatives, dimethyl sulfoxide, lower, optionally N-substituted fatty acid amides and cyclic amides. Individual examples of suitable solvents are methanol, Ethanol, n- and iso-propanol, n-butanol, isobutanol, ethylene glycol, propanediol, Ethylene glycol mono-methyl and ethyl ether, Dlethylene glycol mono-methyl and ethyl ether, Triethylene glycol - mono-methyl and -ethyl ether, tetrahydrofuran, dioxane, toluene, o-, m- and p-xylene or the technical mixtures monochlorobenzene, dimethyl sulfoxide, Acetamide, N-methylacetamide, formamide, dimethylformamide, N-methylpyrrolidone.

For the method according to the invention, such bases are generally as Suitable condensing agents, which under the respective reaction conditions Compounds of the formula III and the end products of the formula I in the corresponding Anion or

Transfer salt. Appropriately, one chooses from the group of such Bases from those that are technically easily accessible and accordingly inexpensive, the are easy to handle and cannot lead to side reactions. So used it is advantageous to use hydroxides and alcoholates of alkali and alkaline earth metals as bases and alkali salts of weak acids.

Examples of such bases are sodium, potassium or lithium hydroxide, Sodium or potassium methylate, ethylate or tert. butylate, calcium hydroxide and Sodium carbonate, potassium carbonate, trisodium phosphate.

The reactants are preferably used in a ratio of 1: 1: 1; the amount of base is also equimolar. An excess of individual components brings usually no benefits.

As indicated above, the reaction temperatures are in the range from -20 to + 150 ° C, but preferably from 15-1000 ° C.

The optimum reaction temperature can vary from the substituents 1 3 R 1113 and X depend, it can easily be determined by a preliminary experiment. In the The reactions are usually complete in about 1 to 6 hours, the reaction time depends in a known way on the temperature.

The compounds of the formula fall after the process according to the invention I as salts from which the free compounds of the formula I are formed by reaction let preserve with a strong acid. Strong acids within the meaning of the invention Processes are those whose acid dissociation constant is greater than that of Compounds of the formula I, preferably mineral acids.

The compounds of formula I, like their salts, are valuable intermediates which are used for the preparation of z. B. can be used by pharmaceuticals, pesticides and dyes. The compounds of the formula I are preferably used in order to prepare compounds of the formula IV therefrom by processes known per se, in which R1 and X have the meanings given above.

Compounds of the formula IV are of great technical internal se, since they have pharmacological importance (J. Amer. Chem.

Soc. 101, 4424 (1979) and as coupling components for dyes can be used (DOS 23 07 445, DOS 27 19 079, DOS 26 11 665, DOS 26 55 522).

The previously known processes for the preparation of compounds of Formula IV are in DOS 23 07 445, DOS 27 19 079 and J. Amer. Chem. Soc. 101, 4424 (1979) described. As already mentioned in DOS 27 19 079, the method runs according to the DOS 23 07 445 only with difficulty and in unsatisfactory yields.

The method according to DOS 27 19 079 has the disadvantage that it starts from propiolic acid derivatives, which are expensive and due to their industrial hygiene and toxicological properties can only be handled with extreme caution, while the J. Amer. Chem. Soc. 101, 4424 (1979) first of all the synthesis of the pyrimidine derivative from the expensive N, N: dimethylurea requires.

With the compounds of the formula I according to the invention, there is now a new one Starting material provided that is a very simple, technically uncomplicated Production of compounds of the formula IV possible.

For the preparation of compounds of the formula IV according to the invention Compounds of the formula I, provided R2 is hydrogen, in a manner known per se decarboxylated. If R2 is not equal to hydrogen, the compound of formula I first saponified and then decarboxylated. Due to the manufacture of the Compounds of the formula I according to the invention from malonic ester derivatives is R2 in the Usually not equal to hydrogen at first.

The saponification of these compounds can very easily in the usual manner with protons or base catalysis, eg. B. be done by gently warming with water in the presence of a weak acid or a weak alkali. In the case of acid saponification, the compounds of the formula I according to the invention with R ″ hydrogen are obtained (formula Ia), while in the case of alkaline saponification their salts (formula Ib), which can also be converted into the free acids of the formula Ia by the action of acids.

In the formulas Ia and Ib, R1 and X have the meanings given above and Me stands for the metal cation of the base used in the saponification.

Cleaves from the two carboxylic acids of the formula Ia according to the invention C02 is easily removed when heated, with a smooth reaction and excellent Yields of the compounds of the formula IV arise.

If you want to prepare compounds of the formula I according to the invention, the earth used as starting material for the preparation of compounds of formula IV should, it is expedient to use industrially available molonic ester derivatives of Formula II, in which 2 ~ R13 = OCH3 or R2 = R13 = OC2H5.

Of particular importance are compounds of the formula IV and therewith also inventive compounds of the formula I in which X is cyano, carbamoyl or mono- or dialkyl-substituted carbamoyl and R1 is hydrogen or alkyl with 1 to 4 carbon atoms.

Except as a starting material for the preparation of compounds of the formula IV, the compounds of the formula I according to the invention are also available as intermediates to be used for the production of pharmaceuticals and pesticides. About that In addition, as C-H-acidic compounds, they provide valuable coupling and condensation components represent, especially for the production of dyes.

The following working examples illustrate the invention and the use of the compounds of the formula I according to the invention for the preparation of compounds of the formula IV.

Parts are parts by weight and percentages are percentages by weight.

Example 1 16.8 parts of cyanoacetamide are suspended in 60 parts of methanol. To this 36 parts of 30% methanolic sodium methylate solution are added. At room temperature will be in 30 Hin.

43.2 parts of ethoxymethylene malonic ester were added dropwise and the mixture was refluxed for 6 h heated. The resulting suspension can be worked up in two ways.

a) It is sucked off. 32 parts of the monosodium salt are obtained in this way of 2-hydroxy-3-cyano-6-pyridonyl-5-carboxylic acid ethyl ester; part of the yield is in the filtrate in this process.

b) The suspension is introduced into 160 parts of water. After careful Acidification with hydrochloric acid is filtered off with suction, washed with a little water and dried. Yield: 36.6 parts of ethyl 2-hydroxy-3-cyano-6-pyridonyl-5-carboxylate of melting point. 288-290 ° C. IR, NMR and UV spectra confirm the structure.

Example 2 a) 19.6 g of N-methylcyanacetamide are dissolved in 60 parts of methanol suspended. To this 36 parts of 30 algae, methanolic sodium methylate solution are added. At room temperature, 43.2 parts of ethoxymethylene malonic ester are added dropwise in 30 minutes and refluxed for 6 h. Then distilled one that The solvent is removed in vacuo, it is taken up in 200 parts of water and carefully acidified with hydrochloric acid. After filtering off with suction and washing and drying, 199.8 parts are obtained (90% of theory) 1-methyl-2-hydroxy-3-cyano-6-pyridonyl-5-carboxylic acid ethyl ester of melting point. 292-2950C.

b) 22.2 parts of 1-methyl-2-hydroxy-3-cyano-6-pyridonyl-5-carboxylic acid ethyl ester are added to 220 parts of 1N sodium hydroxide solution and stirred at 80 ° C. for 30 minutes. By Addition of 12 parts of 10N hydrochloric acid is adjusted to pH 4-5, 2 1/2 hours under reflux heated, cooled to 200C, by adding concentrated hydrochloric acid to pH 2 placed and the 6-hydroxy-3-cyano-pyridon- (2) filtered off. The yield is after drying 120 parts. The product has a melting point of 240 ° C. and is after TLC and melting point identical to the substance prepared according to the literature (DOS 2 719 079).

Further compounds which can be prepared by the process according to the invention are indicated in the table below by specifying the substituents No. R1 112 X Yield 3 C2115 -C2H5 -CN 90% 4 n -C3H7 -C2H5 -CN 92% 5 -C4H9 -C2H5 -CN 85% 6 C5H11 -C 2H5 -CN 89% -7 -CH2-C -C4H9 -C2H5 -CN 84% C2H5 8 -CH2-CH2-OH -C2H5 -CN 86% 9 -CH2-CH-CH-OH -C2H5 -CN 84% 10 02H5 -CH3 -CN 83% 11 CH3 C2H5 -CN 82% 12 -CH2-C6H5 C2H5 -CN 87% 13 -CH3 02H5 -CONH-CH3 63%

Claims (7)

P atentans P rüche compounds of the formula I wherein X is cyano, nitro, acyl, the carboxylic acid ester group, substituted carbamoyl or sulfamoyl, alkyl or arylsulion or the sulfonic acid ester group Rt is hydrogen, optionally substituted alkyl, cycloalkyl, alkenyl, aralkyl or aryl and R2 is hydrogen, an optionally substituted alkyl, Cycloalkyl, alkenyl, aralkyl or phenyl, and their alkali and alkaline earth salts. 2. Compounds of the formula I according to claim 1, characterized in that that X is cyano, nitro, alkylcarbonyl with 1 to 8 carbon atoms, optionally in the phenyl nucleus by one or two substituents from the halogen group, in particular fluorine, chlorine or bromine, nitro, cyano, alkoxy with 1 to 4 carbon atoms, alkyl with 1 to 4 carbon atoms substituted benzylcarbonyl, phenethylcarbonyl or benzoyl, or by alkoxycarbonyl benzoyl substituted with 2 to 5 carbon atoms, alkoxycarbonyl with 1 to 8 0 atoms, C1 to C4 alkoxy or Ci to C4 alkanoylalkoxycarbonyi with 4 to 9 0 atoms, cycloalkoxycarbonyl with 6 to 9 carbon atoms, optionally with one or two substituents in the phenyl nucleus the group halogen, in particular fluorine, chlorine and bromine, alkoxy with 1 to 4 0 atoms, Benzyloxycarbonyl substituted with 1 to 4 carbon atoms, phenethyloxycarbonyl, or phenoxycarbonyl, carbamoyl or sulfamoyl of the formula -CONR4R5 or -SO2NR 4R5 in which R4 and R5 are identical or different and are hydrogen, alkyl with 1 to 8 0 atoms, C1-C4 alkoxy and C1-C4 alkanoyloxyalkyl with 2 to 8 0 atoms, Cycloalkyl with 5 to 8 carbon atoms, optionally with one or two in the phenyl nucleus Substituents from the group halogen, alkoxy with 1 to 40 atoms, alkyl with 1 to 4 C-atoms mean substituted benzyl, phenylethyl or phenyl, alkylsulfonyl with 1 to 8 0 atoms, cycloalkylsulfonyl with 5 or 6 0 atoms, optionally in the phenyl nucleus by one or two substituents from the group halogen, alkoxy with 1 to 4 0 atoms, Benzylsulfonyl, phenethylsulfonyl, phenylsulfonyl substituted by alkyl with 1 to 4 carbon atoms, Alkoxysulfonyl with 1 to 8 0 atoms, cycloalkoxysulfonyl with 5 or 6 0 atoms, in the phenyl nucleus optionally by one or two substituents from the group halogen, Alkoxy with 1 to 40 atoms, alkyl with 1 to 4 carbon atoms substituted benzyloxysulfonyl, Means phenethoxysulfonyl, phenoxysulfonyl. 3. Compounds of the formula I according to claim 1, characterized in that that R1 is hydrogen, straight-chain or branched alkyl having 1 to 12 carbon atoms, whose carbon chain is interrupted by 1 to 5 oxygen atoms or -NR3 groups and that by hydroxy, alkanoyloxy with 1 to 4 carbon atoms, cycloalkoxy with 5 to 8 0 atoms, aryl with 6 to 12 0 atoms, aryloxy with 6 to 12 0 atoms, cyano, amino, Phenylamino, alkanoylamino with 1 to 6 0 atoms, benzoylamino, bonded to nitrogen cyclic amides with 5 to 7 ring members, alkoxycarbonyl with 2 to 9 0 atoms, hydroxyalkoxycarbonyl may be substituted with 3 to 5 carbon atoms, cycloalkyl with 3 to 8 carbon atoms, alkenyl with 3 to 6 0 atoms, aralkyl with 7 to 12 0 atoms, the alkyl chain of which is still through OH can be substituted or aryl with 6 to 12 0 atoms, where contained in R1 Phenyl nuclei or alkyl with a total of up to 6 0 atoms, chlorine or alkoxy be substituted with up to 4 carbon atoms and naphthyl nuclei by methyl or ethyl can, and H3 hydrogen, straight-chain or branched alkyl with 1 to 6 carbon atoms or alkanoyl with 1 or 2 carbon atoms 4. Connections of the formula I according to claim 1, characterized in that R2 is hydrogen or a Metal cation straight-chain or branched alkyl with 1 to 8 carbon atoms, which still by alkoxy with 1 to 40 atoms, aralkoxy with 7 to 12 carbon atoms or aryloxy with 6 to 12 carbon atoms can be substituted, cycloalkyl with 5 to 8 0 atoms, alkenyl with 3 to 6 0 atoms, aralkyl with 7 to 12 carbon atoms or phenyl. 5. Process for the preparation of pyridone derivatives of the general formula I, characterized in that a malonic ester derivative of the formula II wherein R2 has the meanings given in claims 1 and 4 with the exception of hydrogen and R13 is alkyl having 1 to 4 carbon atoms, in an organic solvent in the presence of a base at temperatures from -20 to 1500C with an acetamide derivative of the formula III X -CH2-CONH-R1 (III) in which X and R1 have the meanings given in claims 1 and 3, condensed and, if desired, then prepares the free compound of formula I from the resulting salt of the compound of the formula I by the action of a dilute strong acid and / or the ester group -COOR2 is saponified to a carboxyl group by acidic or alkaline treatment. 6. Use of the compounds of the general formula I in which R is hydrogen for the preparation of valuable, known compounds of the formula IV by decarboxylation in a manner known per se. 7. Use of the compounds of general formula I in which R is not hydrogen, for the production of valuable known compounds of formula IV, by saponification of the ester group -COOR2 and subsequent decarboxylation in a manner known per se.